Re: [PATCH] RDMA/srp (gcc13): force int types for max_send_sge and can_queue

From: Bart Van Assche
Date: Mon Oct 31 2022 - 12:32:10 EST


On 10/31/22 04:45, Jiri Slaby (SUSE) wrote:
Since gcc13, each member of an enum has the same type as the enum [1]. And
that is inherited from its members. Provided "SRP_TAG_TSK_MGMT = 1U << 31",
SRP_MAX_SGE and SRP_TSK_MGMT_SQ_SIZE are unsigned ints.

This results in the following warnings:
include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast
drivers/infiniband/ulp/srp/ib_srp.c:563:42: note: in expansion of macro 'min'

include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast
drivers/infiniband/ulp/srp/ib_srp.c:2369:27: note: in expansion of macro 'min'

Force the use of min_t() instead of min() to use int for all those, as
this is what both targets
target->scsi_host->can_queue
and
init_attr->cap.max_send_sge
are.

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36113

Cc: Martin Liska <mliska@xxxxxxx>
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: linux-rdma@xxxxxxxxxxxxxxx
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
---
drivers/infiniband/ulp/srp/ib_srp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 1075c2ac8fe2..7db487da8293 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -560,7 +560,8 @@ static int srp_create_ch_ib(struct srp_rdma_ch *ch)
init_attr->cap.max_send_wr = m * target->queue_size;
init_attr->cap.max_recv_wr = target->queue_size + 1;
init_attr->cap.max_recv_sge = 1;
- init_attr->cap.max_send_sge = min(SRP_MAX_SGE, attr->max_send_sge);
+ init_attr->cap.max_send_sge = min_t(int, SRP_MAX_SGE,
+ attr->max_send_sge);
init_attr->sq_sig_type = IB_SIGNAL_REQ_WR;
init_attr->qp_type = IB_QPT_RC;
init_attr->send_cq = send_cq;
@@ -2366,7 +2367,7 @@ static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
* bounce requests back to the SCSI mid-layer.
*/
target->scsi_host->can_queue
- = min(ch->req_lim - SRP_TSK_MGMT_SQ_SIZE,
+ = min_t(int, ch->req_lim - SRP_TSK_MGMT_SQ_SIZE,
target->scsi_host->can_queue);
target->scsi_host->cmd_per_lun
= min_t(int, target->scsi_host->can_queue,

I don't like this patch because it changes min() into min_t(). The former checks its arguments types while the latter uses casts and hence ignores most information that is present in the argument types. Please split the enum in ib_srp.h instead of changing min() into min_t().

Thanks,

Bart.